Neutralizing munition

ABSTRACT

A munition is provided for deploying a molten payload within a target. A plurality of holes are formed in the munition&#39;s projectile body about the circumference thereof. A seal closes off each hole. A firing mechanism is mounted in the munition&#39;s nose cone and is capable of generating energy of initiation upon deformation of the nose cone. A first burnable material is housed in the projectile body and is coupled to the firing mechanism to receive the energy of initiation. The first burnable material extends in a tree-like fashion along a plurality of connected paths in the projectile body with each of the connected paths terminating at one of the seals. A second burnable material fills the voids in the projectile body surrounding the first burnable material. The first burnable material has a lower threshold of combustion than the second burnable material while the second burnable material burns hotter than the first burnable material.

ORIGIN OF THE INVENTION

The invention described herein was made in the performance of officialduties by employees of the Department of the Navy and may bemanufactured, used, licensed by or for the Government for anygovernmental purpose without payment of any royalties thereon.

FIELD OF THE INVENTION

The invention relates generally to munitions, and more particularly to amunition capable of neutralizing a target while minimizing theprobability of an explosive event.

BACKGROUND OF THE INVENTION

Underwater mines are varied in their designs and mechanisms for sensingwhen detonation should occur. Such sensing systems include mechanical,electrical, acoustic, heat, optical, or other types of sensors.Regardless of the type of mine, underwater mine neutralization typicallyinvolves the direct placement of an explosive material on a mine orinvolves a projectile-delivered explosive that will impact the mine andcause an explosive event. Both of these methods have drawbacks. In termsof direct placement of a bulk explosive, underwater divers must be usedto place the explosive directly on a mine. The explosive could be setoff prematurely or accidentally and injure/kill the diver. Further, thediver is generally at risk just swimming amongst underwater mines. Stillfurther, whether directly-placed or projectile-delivered, the resultingexplosive event signals to an enemy that operations of some sort may beunderway. This could compromise the covert nature of a mission.

SUMMARY OF THE INVENTION

Accordingly, it is an object of the present invention to provide amunition that can be directed/delivered to a target for theneutralization thereof without the use of an explosive event.

Another object of the present invention is to provide a munition thatcan be used to neutralize an underwater mine without endangeringpersonnel.

Still another object of the present invention is to provide a munitionthat can be used to neutralize an underwater mine without causing theunderwater mine to detonate.

Other objects and advantages of the present invention will become moreobvious hereinafter in the specification and drawings.

In accordance with the present invention, a munition is provided fordeploying a molten payload within a target. The munition has aprojectile body with a nose cone. A plurality of holes are formed in theprojectile body about a circumference thereof. A seal closes off eachhole. A firing mechanism is mounted in the nose cone and is capable ofgenerating energy of initiation upon deformation of the nose cone. Afirst burnable material is housed in the projectile body and is coupledto the firing mechanism to receive the energy of initiation. The firstburnable material extends in a tree-like fashion along a plurality ofconnected paths in the projectile body with each of the connected pathsterminating at one of the seals. Voids are formed in the projectile bodyaround the connected paths. A second burnable material fills the voidsin the projectile body. The first burnable material has a lowerthreshold of combustion than the second burnable material. Uponimpacting a target, deformation of the nose cone activates the firingmechanism. As a result, the energy of initiation is applied to the firstburnable material which burns quickly along the connected paths andcauses the failure of the seals. The heat generated by the burning ofthe first burnable material ignites the second burnable material which,in turn, becomes molten and flows out of the unsealed holes in theprojectile body.

BRIEF DESCRIPTION OF THE DRAWINGS

Other objects, features and advantages of the present invention willbecome apparent upon reference to the following description of thepreferred embodiments and to the drawings, wherein correspondingreference characters indicate corresponding parts throughout the severalviews of the drawings and wherein:

FIG. 1 is a cross-sectional schematic view of one embodiment of amunition that can deploy a molten pyrotechnic payload within a target inaccordance with the present invention; and

FIG. 2 is a cross-sectional view of an embodiment of a firing mechanismthat can be used in the munition of the present invention.

DETAILED DESCRIPTION OF THE INVENTION

Referring now to the drawings, and more particularly to FIG. 1, amunition that can deploy a molten payload within a target is shownschematically and referenced generally by numeral 10. Munition 10 can beused to neutralize (i.e., render the target inoperable) a variety oftargets. For example, such targets can include underwater mines,vehicles, facilities, electronic equipment, or any other target that canbe rendered useless by the deposition of a molten pyrotechnic materialtherein. In terms of an underwater target, munition 10 can be launchedusing, for example, the launcher disclosed in U.S. Pat. No. 5,686,686.

Munition 10 has an outer body 12 shaped like a projectile, theparticular shape of which is not a limitation of the present invention.Projectile body 12 has a nose cone 14 and a casing 16 aft of andadjoining nose cone 14. Nose cone 14 houses a firing mechanism 18 thatwill initiate reactions within casing 16 as will be described furtherbelow. Firing mechanism 18 can be of any suitable design that suppliesan energy of initiation when munition 10 embeds itself in a target.Typically, firing mechanism 18 will be triggered upon the deformation ofnose cone 14. Since nose cone 14 will generally be made from a heavymetal (e.g., titanium, tungsten, depleted uranium, stainless steel,etc.) so that it can puncture a target upon impact therewith. The use ofa heavy metal also prevents inadvertent activation of firing mechanism18 as routine mishandling of munition 10 will not bring about sufficientdeformation of nose cone 14 to initiate firing mechanism 18.

A number of holes 16A are formed about the circumference of casing 16.While the size of holes 16A is not a limitation of the presentinvention, holes 16A typically are on the order of approximately 0.25inches. Each of holes 16A is sealed with a seal or plug 20 that willfail (e.g., melt, break, etc.) at the appropriate time as will beexplained further below. Each seal 20 serves as a moisture seal and canbe a soft meltable plastic or wax, a piece of foil or other suitablesealing material.

Coupled to firing mechanism 18 is a burnable material 30 that extendsfrom firing mechanism 18 in a tree-like structure to define a pluralityof connected paths. By way of example, burnable material 30 has acentral trunk portion 30A extending axially within and along the lengthof casing 16. A plurality of branch portions 30B of burnable material 30extend radially outward from trunk portion 30A to a hole 16A closed offby a seal 20. Note that not all of holes 16A need to have a branchportion 30A leading thereto although this will generally be the case.Branch portions 30B need not extend perpendicularly from trunk portion30A, but could also be at an angle thereto. Both of trunk portion 30Aand branch portions 30B need not define straight paths as shown, butcould be curved. Still further, more than one of trunk portion 30A couldextend the length of casing 16.

The spaces or voids formed about burnable material 30 within casing 16is filled with another burnable material 40. Relative to burnablematerial 30, burnable material 40 has a higher threshold of combustionand burns at higher temperature than burnable material 30. That is,material 30 will combust more readily than material 40 but, once ignitedto its molten state, material 40 attains higher temperatures than aburning form of material 30.

The interior configuration of burnable material 30 and burnable material40 can be achieved in a variety of ways. For example, tubes 32 definingthe tree-like structure of burnable material 30 can be filled and placed(or placed and filled) within casing 16. Tubes 32 could be made from amaterial (e.g., cardboard, plastic, etc.) that burns or melts easilywhen burnable material 30 is burning. With filled tubes 32 in place,burnable material 40 can be added to casing 16 to fill up the spaces andtubes 32. Another way to achieve the interior configuration of burnablematerials 30 and 40 is to first fill casing 16 with burnable material40, and then bore out burnable material 40 to define the desiredtree-like structure for burnable material 30. The bored out portion ofburnable material 40 is then filled with a slurry of burnable material30. In this construction, no tubes 32 would be required.

In operation, munition 10 is launched towards a target (not shown). Uponimpacting the target, nose cone 14 penetrates an outer wall of thetarget, begins to deform, and pulls casing 16 inside the target. Sincemost mines today are equipped with sensor(s) that are designed toprevent detonation due a brief sudden impact (e.g., bumping by a fish ora speedboat, or impact by munition 10), munition 10 will typically beable to penetrate a mine without detonating it. To assure that munition10 does not just pass through the target, casing 16 can be flaredoutward at some portion thereof to define a larger outer diameter. Forexample, in the illustrated embodiment, casing 16 flares radiallyoutward at a step 16B. However, it is to be understood that this is notthe only construction for casing 16. Such flaring could also occurcontinuously along the length of casing 16. obviously, such flaringshould not negatively impact the ballistic nature of munition 10.

Deformation of nose cone 14 activates firing mechanism 18 which, inturn, supplies an energy of initiation to burnable material 30 to bringabout two results. First, burnable material 30 burns quickly along itstrunk portion 30A and branch portions 30B causing the failure (e.g.,melting) of seals 20. Second, the heat generated by the burning ofburnable material 30 ignites burnable material 40 throughout casing 16.As burnable material 40 becomes molten and pressurized due to thermalexpansion, it flows out of any of holes 16A aligned with burnablematerial 30, as well as any of holes 16A aligned with burnable material40 whose seals 20 will fail as burnable material 40 becomes molten.

Material(s) selected for burnable material 40 will dictate thetemperature thereof in its molten state, how the material will flow outof casing 16 in its molten state, and the choice of burnable material30. Several examples will be provided herein. However, it is to beunderstood that other material selections can be made without departingfrom the scope of the present invention.

Regardless of the type of molten flow desired, a good choice forburnable material 40 is thermite which, in general, is a mixture ofaluminum and ferrous oxide. If it is desired to provide a continuousflow of (molten) burnable material 40 from casing 16, burnable material40 could be selected from a variety of well known thermite compoundssuch as thermite TH3 (66.8% aluminum/iron oxide, 29.00% barium nitrate,2.00% sulfur and a percentage of binder). Other thermite compounds thatcan be used in the present invention include, but are not limited to, athermite compound that includes a copolymer of vinylidene fluoride andhexafluoroporpylene as disclosed in U.S. Pat. No. 4,432,816, or athermite compound that includes metallic fuels and halopolymeric binderslike polytetrafluroethylene as disclosed in U.S. Pat. No. 4,349,396.

In other applications, it may be desirable to create a turbulent orchuffing flow of (molten) burnable material 40. That is, (molten)burnable material 40 is forced out of holes 16A turbulently in ajet-like fashion. To achieve this, burnable material 40 is ahigh-temperature burning material (e.g,. a thermite compound) withenergetic or explosive material homogeneously dispersed therein. Theexplosive material could be in the form of powder, solid particles, orhollow particles or pellets. Suitable explosive materials include, butare not limited to, TNT including specific military compositions such asPENTOLITE, RDX including specific military composition such as variousHBX compositions, and HMX including specific military compositions suchas OCTOL. The explosive material can be of any shape/size as needed toincrease or reduce its burning rate and/or transition from burning todeflagration and/or detonation depending on the burning temperature ofthe burning material (e.g., thermite compound) and cook-off temperatureof the explosive material.

The amount of explosive material dispersed in the burning material(e.g., thermite compound) can be varied based on the type of chuffingreaction desired. In terms of burning materials selected from thermitecompounds, the weight percent of explosive material used to make theburnable material 40 could be as high as 80%. The actual weight percentof explosive material depends on a variety of factors such as the choiceof explosive, percentage of voids in the material mixture, pressuredeveloped in the material as it is being loaded/packed into casing 16,and the operation pressure and temperature of the material as it burns.

The choice of burnable material 30 can also be varied without departingfrom the scope of the present invention. By way of example, if burnablematerial 40 is a thermite compound, or a mixture of a thermite compoundand explosive material as described above, burnable material 30 could beany well known thermite ignition mix. One such thermite ignition mix ismade from the following constituent components (or suitable facsimilesas known in the art of thermite ignition mixes):

Potassium Nitrate 66.89% by weight Titanium 14.96% Silicon 7.78%Aluminum 8.67% Binder 1.70%

If it is necessary to make burnable material 30 in the form of a slurry,a variety of well established practices can be used. For example, aslurry could be made using the above-recited thermite ignition mix byadding eight percent by weight of nitrocellulose to acetone, and thenmixing twenty grams of the acetone/nitrocellulose solution with fifteengrams of the above-recited thermite ignition mix.

As mentioned above, a variety of designs could be used for firingmechanism 18 without departing from the scope of the present. By way ofexample, one suitable firing mechanism 18 is illustrated in FIG. 2. Afiring pin 180 is housed within a retainer housing 181 having, forexample, a retaining clip 182 cooperating with a detent 183 on firingpin 180. Clip 182/detent 183 prevent the inadvertent activation offiring mechanism 18. A primer 184 (such as military primer M42C2) isadjacent housing 181 and maintained within a primer and ignition holder185. Adjacent primer 184 within holder 185 is any igniter 186 (such asIGNITER 212 described on U.S. Navy Drawing DWG 2518212) which, in turn,is in contact with burnable material 30. At target impact, nose cone 14deforms and causes firing pin 180 to impact primer 184 as clip 182fails. Note that the requirement that nose cone 14 be deformed prior toinitiation of firing mechanism 18 provides for the penetration of nosecone 14 into the target prior to full activation of firing mechanism 18.This insures that munition 10 is substantially in the target prior tothe deployment of (molten) burnable material 40. The impact of firingpin 180 on primer 184 initiates igniter 186 to start the burning ofburnable material 30 along its defined paths as described above.

The advantages of the present invention are numerous. The munition canbe used to neutralize an underwater mine or other target without anyexplosive event thereby increasing the chance for mission covertness.The munition can be remotely directed and launched towards its targetthereby keeping personnel out of harms way. The present invention islightweight and can be used on land or underwater. The munition can beconstructed to provide a continuous flow or a chuffing flow of moltenmaterial.

Although the invention has been described relative to a specificembodiment thereof, there are numerous variations and modifications thatwill be readily apparent to those skilled in the art in light of theabove teachings. For example, as mentioned above, energy of initiationfor igniting burnable material 30 could come from a variety ofmechanisms such as percussion primers, squibs, exploding bridge wires, ashock tube, exploding foil initiators, an underwater timing fuse, etc.The choice of burnable materials 30 and 40 can be different from thosedescribed herein without departing from the novelty of the presentinvention. It is therefore to be understood that, within the scope ofthe appended claims, the invention may be practiced other than asspecifically described.

What is claimed as new and desired to be secured by Letters Patent ofthe United States is:
 1. A munition for deploying a molten payloadwithin a target, comprising: a projectile body having a nose cone, saidprojectile body having a plurality of holes formed therethrough about acircumference thereof; a seal for closing off each of said plurality ofholes; a firing mechanism mounted in said nose cone for generatingenergy of initiation upon deformation of said nose cone; a firstburnable material housed in said projectile body and coupled to saidfiring mechanism to receive said energy of initiation, said firstburnable material extending in a tree-like fashion along a plurality ofconnected paths in said projectile body, each of said plurality ofconnected paths terminating at one said seal, wherein voids are formedin said projectile body around said plurality of connected paths; asecond burnable material filling said voids in said projectile body; andsaid first burnable material having a lower threshold of combustion thansaid second burnable material.
 2. A munition as in claim 1 wherein saidprojectile body flares radially outward at a portion thereof aft of saidnose cone.
 3. A munition as in claim 1 wherein said second burnablematerial is a thermite compound.
 4. A munition as in claim 1 whereinsaid second burnable material is a thermite compound having an explosivematerial dispersed therein.
 5. A munition as in claim 4 wherein saidexplosive material is in a form selected from the group consisting ofpowder, particles, solid pellets and hollow pellets.
 6. A munition as inclaim 4 wherein a mixture is formed by said explosive material dispersedin said thermite compound, said mixture comprising up to approximately80% by weight of said explosive material.
 7. A munition as in claim 1wherein said plurality of connected paths comprises: at least one trunkpath extending from said firing mechanism to an aft portion of saidprojectile body; and a plurality of branch paths coupled to said trunkpath with each of said plurality of branch paths terminating at one saidseal.
 8. A munition as in claim 1 wherein said nose cone is made from amaterial selected from the group consisting of titanium, tungsten,depleted uranium and stainless steel.
 9. A munition as in claim 1further comprising tubes defining said plurality of connected pathswherein said first burnable material is housed in said tubes prior toreceiving said energy of initiation.
 10. A munition as in claim 1wherein said second burnable material has an explosive materialdispersed therein.
 11. A munition as in claim 10 wherein said explosivematerial is in a form selected from the group consisting of powder,particles, solid pellets and hollow pellets.
 12. A munition as in claim1 wherein said seal comprises a material that fails when said firstburnable material burns in response to said energy of initiation.
 13. Amunition for deploying a molten payload within a target, comprising: aprojectile body having a nose cone, said projectile body expanding indiameter aft of said nose cone, said projectile body having a pluralityof holes formed therethrough about a circumference thereof; a seal forclosing off each of said plurality of holes, each said seal made from ameltable material; a firing mechanism mounted in said nose cone forgenerating energy of initiation upon deformation of said nose cone; afirst burnable material housed in said projectile body and coupled tosaid firing mechanism to receive said energy of initiation, said firstburnable material extending in a tree-like structure having a trunk pathand a plurality of branch paths connected to said trunk path, each ofsaid plurality of branch paths extending radially outward from saidtrunk path to one said seal, wherein voids are formed in said projectilebody around said trunk path and said plurality of branch paths; a secondburnable material filling said voids in said projectile body; and saidfirst burnable material having a lower threshold of combustion than saidsecond burnable material.
 14. A munition as in claim 13 wherein saidsecond burnable material has an explosive material dispersed therein.15. A munition as in claim 14 wherein said explosive material is in aform selected from the group consisting of powder, particles, solidpellets and hollow pellets.
 16. A munition as in claim 13 wherein saidsecond burnable material is a thermite compound.
 17. A munition as inclaim 16 wherein said second burnable material is a thermite compoundhaving an explosive material dispersed therein.
 18. A munition as inclaim 17 wherein said explosive material is in a form selected from thegroup consisting of powder, particles, solid pellets and hollow pellets.19. A munition as in claim 17 wherein a mixture is formed by saidexplosive material dispersed in said thermite compound, said mixturecomprising up to approximately 80% by weight of said explosive material.20. A munition as in claim 13 wherein said nose cone is made from amaterial selected from the group consisting of titanium, tungsten,depleted uranium and stainless steel.
 21. A munition as in claim 13further comprising tubes defining said plurality of connected pathswherein said first burnable material is housed in said tubes prior toreceiving said energy of initiation.